1. Field of the Invention
The present invention relates to a pneumatic tyre for a car. In particular a pneumatic tyre for High Performance cars and SUV's (Sport Utility Vehicles).
2. Description of the Related Art
Optimal characteristics in terms of traction and braking, as well as handling on dry and wet road surfaces are usually required from tyres of this class, in addition to a satisfactory resistance to wear.
Tyres for motor-vehicles are known which have a tread provided with blocks delimited by circumferential grooves extending in a substantially longitudinal direction, and transverse grooves extending in a substantially axial direction. The blocks resulting from interlacing of these grooves are shaped according to different conformations suitably studied and are disposed in circumferential side-by-side rows each of which is included between two successive circumferential grooves.
The circumferential grooves can affect the features concerning the tyre's steering property and steadiness on running in relation to the lateral (slip) thrusts directed parallel to the rotation axis of the tyre.
The transverse grooves, in turn, can affect the traction ability features of the tyre, i.e. the capability of transmitting to the road surface the tangential thrusts parallel to the running direction, during the acceleration and breaking steps of the vehicle.
The circumferential and transverse grooves can also affect water draining in the contact area with the road surface (footprint area) during running on a wet road surface.
WO 2006-007877 in the name of the same Applicant, proposes a tyre the tread band of which has at least one first and one second circumferential groove separating a central portion from two shoulder portions. A circumferential cut is formed some distance from at least one of the circumferential grooves.
The tread band is crossed by transverse grooves distributed according to circumferentially repeated modules, each of which in at least one shoulder portion has a main groove with a first substantially rectilinear segment inclined at an angle included between 3° and 10° relative to a radial plane of the tyre, a second substantially rectilinear segment extending between the circumferential cut and the first circumferential groove at an angle just as an indication included between 105° and 130° relative to the radial plane, and a curvilinear connecting segment between the first and second segments.